This is Romney's campaign to lose

ELEMENTS of the commentariat are demanding a Sister Souljah moment from Mitt Romney. The call harks back to 1992 when candidate Bill Clinton gave the African-American rapper a jab in the ribs for her crazy call for a week in which blacks would kill whites, instead of each other.

But Romney is reluctant when it comes to shoving campaign surrogates - real and wannabes - who shoot off their mouth.

He allowed them to blackball his briefly appointed foreign policy spokesman because the guy was openly gay. He would not rebuke radio loudmouth Rush Limbaugh for branding a Georgetown University student a ''slut'' and a ''prostitute'' after she testified to Congress about contraception. And he did not challenge a supporter whose call for Barack Obama to be tried for treason won cheers at a Romney rally.

So what happened on Tuesday? That was the night Romney finally locked in the Republican presidential nomination, winning the Texas primary to secure more than the 1144 convention delegates he needs and to finally shake Newt Gingrich and the rest of the oddball pack seeking the nomination.

But with whom did Romney share this day of triumph? None other than self-promoter extraordinaire Donald Trump, who at the weekend was denounced by the dean of conservative commentators, George F. Will, as a ''bloviating ignoramus''.

The Romney plan was to use his big day to stay focused on the economy, with a new attack on some of the Obama administration's less-than-successful mega-grants to dodgy businesses. But the day's media oxygen was sucked away as Trump resurrected the issue of the President's American birth - "a lot of people do not think [Obama's] was an authentic [birth] certificate", Trump told CNN before hosting a Romney fund-raiser in Las Vegas.

Romney is right about the economy he's wrong in his choice of podium pal.

This is an exceptionally tight campaign and there will be days dominated by social issues: same-sex marriage, ''don't-ask, don't-tell'', abortion and birth control. But the 1992 quip by Clinton strategist James Carville holds good in 2012 - ''it's the economy, stupid''.

It is Romney's campaign to lose. He's cashed up and thousands will come to listen. But this is the campaign phase in which he must sell himself to Americans, and that requires him to believably shape the chapters of his life that he avoids on the stump ? before the Obama team hijacks them to use as a weapon against him.

He uses his tenure at Bain Capital as the narrow focus of a campaign - ''I'm a successful businessman and I can turn this country around'' - which he wants to frame as a referendum on Obama's first term. But after initial knife work by Romney's Republican competitors, Obama now stabs at Romney the businessman, shaping the campaign as a choice - Obama or Romney.

The Obama campaign has just begun to reveal how it will use Romney's virtually unacknowledged tenure as governor of Massachusetts, in particular his healthcare reform law that was the template for Obamacare. In essence, it will explore issue by issue how the Boston moderate became a self-described ''severe conservative''.

And it is likely that Democrat surrogates will take up the other issue that Romney neglects on the stump: his Mormon faith and the politically fertile belief by some Americans that it is more cult than creed.

Obama remains the engager-in-chief. But barely sheathed beneath all the charisma is a ruthless politician going for broke. He has set a record for first-term fund-raisers, 191, which exceeds the combined total of his predecessors from Jimmy Carter through to George W. Bush.

Only 1.6 per cent, in Obama's favour, separates the two men in Real Clear Politics' average of national opinion polls. Amid murmuring in the Democratic camp that negative campaigning is a high-risk strategy for Obama, it seems to be where the President is going.

This is how the Obama gamble works: as a personally popular president (50-plus per cent), he can command the ear of voters to persuade them that the less personable Romney (high-30s) is a political fraud, before Romney can win their attention.

But despite wall-to-wall media coverage, they will make their cases in a handful of swing states. Playing in particular to women, Hispanics and young voters, the Obama campaign will attempt to lock in a winner's margin of Electoral College votes in four strategic plays - Colorado, New Mexico, Nevada and Iowa or Ohio and Iowa or North Carolina and Virginia or in Florida alone.

I have been inclined to go with a line of analysis that argues Romney is not unlike Obama in that he is a centrist, a pragmatist who, as president, would not let ideology get in the way of resolving a policy crisis.

Wrong, says Richard Cohen in The Washington Post. And the logic here might explain why Romney does not push back on the surrogates - Cohen argues that Romney's policy flip-flops are proof that as a candidate he is, and as a president he would be, clay in the hands of the likes of the Republican hard-liners and Tea Partiers.

But amid great economic uncertainty, after almost four years of Obama, the Romney stump speech appeals to voter self-interest.

"Is it easier to make ends meet?" he asks. "Is it easier to sell your home or buy a new one? Have you saved what you need for retirement? Are you making more in your job? Do you have a better chance to get a better job? Do you pay less at the pump?"

Sell that before Obama can chop through the rest of his platform and the White House is Romney's.

Paul McGeough is The Age's chief correspondent, based in Washington.